/**
 * Software License, Version 1.0
 * 
 * Copyright 2003 The Trustees of Indiana University.  All rights reserved.
 * 
 *
 *Redistribution and use in source and binary forms, with or without 
 *modification, are permitted provided that the following conditions are met:
 *
 *1) All redistributions of source code must retain the above copyright notice,
 * the list of authors in the original source code, this list of conditions and
 * the disclaimer listed in this license;
 *2) All redistributions in binary form must reproduce the above copyright 
 * notice, this list of conditions and the disclaimer listed in this license in
 * the documentation and/or other materials provided with the distribution;
 *3) Any documentation included with all redistributions must include the 
 * following acknowledgement:
 *
 *"This product includes software developed by the Community Grids Lab. For 
 * further information contact the Community Grids Lab at 
 * http://communitygrids.iu.edu/."
 *
 * Alternatively, this acknowledgement may appear in the software itself, and 
 * wherever such third-party acknowledgments normally appear.
 * 
 *4) The name Indiana University or Community Grids Lab or NaradaBrokering, 
 * shall not be used to endorse or promote products derived from this software 
 * without prior written permission from Indiana University.  For written 
 * permission, please contact the Advanced Research and Technology Institute 
 * ("ARTI") at 351 West 10th Street, Indianapolis, Indiana 46202.
 *5) Products derived from this software may not be called NaradaBrokering, 
 * nor may Indiana University or Community Grids Lab or NaradaBrokering appear
 * in their name, without prior written permission of ARTI.
 * 
 *
 * Indiana University provides no reassurances that the source code provided 
 * does not infringe the patent or any other intellectual property rights of 
 * any other entity.  Indiana University disclaims any liability to any 
 * recipient for claims brought by any other entity based on infringement of 
 * intellectual property rights or otherwise.  
 *
 *LICENSEE UNDERSTANDS THAT SOFTWARE IS PROVIDED "AS IS" FOR WHICH NO 
 *WARRANTIES AS TO CAPABILITIES OR ACCURACY ARE MADE. INDIANA UNIVERSITY GIVES
 *NO WARRANTIES AND MAKES NO REPRESENTATION THAT SOFTWARE IS FREE OF 
 *INFRINGEMENT OF THIRD PARTY PATENT, COPYRIGHT, OR OTHER PROPRIETARY RIGHTS. 
 *INDIANA UNIVERSITY MAKES NO WARRANTIES THAT SOFTWARE IS FREE FROM "BUGS", 
 *"VIRUSES", "TROJAN HORSES", "TRAP DOORS", "WORMS", OR OTHER HARMFUL CODE.  
 *LICENSEE ASSUMES THE ENTIRE RISK AS TO THE PERFORMANCE OF SOFTWARE AND/OR 
 *ASSOCIATED MATERIALS, AND TO THE PERFORMANCE AND VALIDITY OF INFORMATION 
 *GENERATED USING SOFTWARE.
 */
package cgl.narada.jms;

import javax.jms.JMSException;
import javax.jms.Topic;
import javax.jms.TopicSubscriber;

/**
 * A client uses a TopicSubscriber object to receive messages that have been
 * published to a topic. A TopicSubscriber object is the publish/subscribe form
 * of a message consumer.
 * 
 * A TopicSession allows the creation of multiple TopicSubscriber objects per
 * topic. It will deliver each message for a topic to each subscriber eligible
 * to receive it. Each copy of the message is treated as a completely separate
 * message. Work done on one copy has no effect on the others; acknowledging one
 * does not acknowledge the others; one message may be delivered immediately,
 * while another waits for its subscriber to process messages ahead of it.
 * 
 * Regular TopicSubscriber objects are not durable. They receive only messages
 * that are published while they are active. Messages filtered out by a
 * subscriber's message selector will never be delivered to the subscriber. From
 * the subscriber's perspective, they do not exist.
 * 
 * In some cases, a connection may both publish and subscribe to a topic. The
 * subscriber NoLocal attribute allows a subscriber to inhibit the delivery of
 * messages published by its own connection.
 * 
 * @author Shrideep Pallickara $Revision$ $Date$
 */

public class JmsTopicSubscriber extends JmsMessageConsumer implements
    TopicSubscriber, JmsDebugFlags {

    /** The JMS-Session which created this TopicSubscriber */
    private JmsTopicSession jmsTopicSession;

    /** The name used to identify the subscriber */
    private String subscriptionIdentifier;

    /**
     * NoLocal attribute allows a subscriber to inhibit the delivery of messages
     * published by its own connection.
     */
    private boolean noLocal = false;

    /** The specified messageSelector for this subscriber */
    private String messageSelector;

    /** The JmsSelector */
    private JmsSelector jmsSelector;

    /** The Topic */
    private Topic topic;

    /** Indicates if it is a durable subscriber */
    private boolean isDurable = false;

    /** Created in JmsTopicSession */
    public JmsTopicSubscriber(JmsTopicSession jmsTopicSession, Topic topic,
        String name, String msgSelector, boolean noLocal) throws JMSException {

        this.topic = topic;
        this.jmsTopicSession = jmsTopicSession;
        if (name != null) {
            isDurable = true;
            subscriptionIdentifier = name;
        }

        if (JmsTopicSubscriber_Debug) {
            System.out.println("JmsTopicSubscriber:: Topic = ("
                + topic.getTopicName() + ") & Message Selector = ("
                + msgSelector + ")");
            if (!noLocal) {
                System.out.println("Need to receive messages published by this"
                    + " connection!!");
            }
        }

        if (msgSelector != null) {
            /**
             * Proceed to initialize the JMS Selector, if there is an] error in
             * the selector specification, there will be a JMS Exception that
             * will be thrown.
             */
            messageSelector = msgSelector;
            jmsSelector = new JmsSelector(messageSelector);
        }

        this.noLocal = noLocal;

        /*
         * if (JmsTopicSubscriber_Debug) { System.out.println("\n" + "Topic
         * Subscriber Initialized:: Topic = (" + topic + ") Subscription Name=(" +
         * name + ") & Message Selector = (" + messageSelector +"\n"); }
         */
        propagateSubscriptionToBroker();
    }

    /** What we need to propagate is simply the JMS Topic Name */
    public void propagateSubscriptionToBroker() throws JMSException {
        NBJmsInterconnectionBridge nbBridge = getBridge();
        String subscription = topic.getTopicName();
        
        nbBridge.initializeConsumer(subscription, isDurable);
    }

    public void unSubscribe() throws JMSException {
        NBJmsInterconnectionBridge nbBridge = getBridge();
        String subscription = topic.getTopicName();

        nbBridge.unSubscribeConsumer(subscription);
    }

    public Topic getTopic() throws JMSException {
        return topic;
    }

    public String getMessageSelector() {
        return messageSelector;
    }

    public JmsSelector getJmsSelector() {
        return jmsSelector;
    }

    /**
     * Gets the <code>NoLocal</code> attribute for this subscriber. The
     * default value for this attribute is false.
     * 
     * @return true if locally published messages are being inhibited
     * @exception JMSException
     *                if the JMS provider fails to get the NoLocal attribute for
     *                this topic subscriber due to some internal error.
     */
    public boolean getNoLocal() throws JMSException {
        return noLocal;
    }

    private NBJmsInterconnectionBridge getBridge() {
        JmsTopicConnection jmsTopicConnection = jmsTopicSession
            .getJmsTopicConnection();
        NBJmsInterconnectionBridge nbBridge = jmsTopicConnection
            .getNbJmsInterconnectionBridge();
        
        return nbBridge;
    }

}
